Several communication systems and applications use time-frequency division multiple access for allocating time and frequency resources among multiple communication terminals. Such multiple access methods typically divide the time and frequency domains into discrete segments, and allocate the segments to communication terminals for transmitting data. One type of time-frequency division multiple access scheme is orthogonal frequency division multiple access (OFDMA), which is used, for example, in communication systems based on the IEEE 802.16 family of standards, commonly referred to as WiMAX. Information regarding these standards is available at www.ieee802.org/16 and at www.wimaxforum.org.
Mobile WiMAX applications often conform to the IEEE 802.16e-2005 standard, entitled “IEEE Standard for Local and Metropolitan Area Networks—Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems—Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1,” which is incorporated herein by reference. Sections 8.4.4.5, 8.4.5.4, 8.4.5.4.1 and 8.4.5.4.2 of the standard describe uplink resource allocation.